Anemias

Anemia due to the faulty construction of red blood cells may occur in infections, chronic diseases (such as of the kidneys), and disorders of the spleen. Mechanical interference with the bone marrow results in anemia in such diseases as leukemia. Failure of blood formation may also be brought on by poisoning or irradiation injury.
The hemolytic anemias cover a wide variety of conditions in which the red blood cells are destroyed, a dramatic example being transfusion reactions from the use of incompatible blood. Chemical agents, including certain drugs; infections, such as malaria; vegetable and animal poisons, for example, snake venom; and various diseases, for example, Hodgkin's disease, are other important causes. Also in this category are congenital anemias in which the defect in the red blood cell is an inherited trait: congenital hemolytic jaundice, sickle-cell anemia, and Mediterranean anemia. Congenital hemolytic jaundice is successfully treated by splenectomy. For sickle-cellanemia and Mediterranean anemia, there is no known effective treatment.
The occurence of anemia secondary to acute blood loss is usually corrected by the transfusion of whole blood. The correction of anemia from chronic blood loss ultimately depends on correction of the underlying defect.